Diazo compounds obtained by coupling acetoacetanilides with tetrazotized diaminobenzanilides

ABSTRACT

Yellow pigments having a greenish hue are represented by the formula: ##STR1## wherein X 1  and X 2  may be the same or different from one another and each is hydrogen, halogen (chlorine, fluorine or bromine), lower alkyl or alkoxy having from 1 to 3 carbon atoms; and wherein R 1  and R 2  may be the same or different from one another and each is the residue from an acyl-acetyl-amino-aromatic coupling agent or the residue from a pyrazolone coupling agent. Pigments are obtained by coupling of (1) an aceto-acetyl-amino-aromatic compound or (2) of a pyrazoline, with a 4,4&#39;-diamino-benzanilide. The yellow pigments have the characteristic of having a high tintorial yield, a high degree of purity of tone (brightness), a good fastness to light, and good resistance to organic solvents. These pigments are particularly useful in the polychrome graphic industry.

This is a continuation of application Ser. No. 274,620, filed July 24,1972, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to certain novel diazo pigments, to amethod of their preparation, and to their application in thepigmentation of organic materials.

2. Description of the Prior Art

The demand for yellow pigments with a high tinctorial yield, having ahigh degree of purity of tone (brightness), a good fastness to light,and good resistance to organic solvents, has been increasing,particularly in the polychrome graphic industry.

Printing inks prepared with yellow pigments should display goodrheological properties, even at high pigment concentrations, and printsprepared with them should be bright and transparent.

It is known that particularly valuable yellow pigments are those whichshow a greenish yellow hue, inasmuch as one of the basic uses of yellowpigments is in obtaining, in admixture with blue pigments, green colors.Yellow pigments having a greenish yellow hue, when admixed with bluepigments, give green colors that tend to be both purer and brighter.

The need for yellow pigments to be of high tinctorial yield, goodtransparency, and of a satisfactory light fastness, has heretoforeprimarily been satisfied by the benzidine pigments. These pigments have,however, certain limits in various industrial applications because theyshow a high oil absorption, which tends to decrease the flowability ofthe pigments present in high concentration. Moreover, such pigments donot exhibit an altogether satisfactory transparency, whichcharacteristic is very important in graphic polychrome printing.

In addition, benzidine pigments have the disadvantage that theirpreparation involves the handling and use of benzidine derivatives suchas, for instance, 3,3'-dichloro-benzidine, which is highly toxic andrequires very strict standards for handling and useage.

SUMMARY OF THE INVENTION

We have surprisingly found that certain novel diazo pigments exhibit, incomparison to benzidine pigments, the advantage of yielding yellow hueswith a markedly more greenish hue and of a considerably greatertransparency. Moreover, our novel pigments are easily prepared withoutthe need for elaborate safety measures.

The pigments of our invention are of the following Formula (I) ##STR2##wherein X₁ and X₂ may be the same or different from one another and eachis hydrogen, halogen (chlorine, fluorine or bromine), lower alkyl oralkoxy having from 1 to 3 carbon atoms; and wherein R₁ and R₂ may be thesame or different from one another and each is the residue from anacyl-acetyl-amino-aromatic coupling agent or the residue from apyrazolone coupling agent.

Preferred diazo pigments of our invention are of the Formula (II)##STR3## wherein X₁ and X₂ are as previously defined; and wherein Y₁ andY₂ may be the same or different from one another and each is phenyl;substituted phenyl wherein the substituents are halogen (chlorine,fluorine or bromine), alkyl having from 1 to 3 carbon atoms, alkoxyhaving from 1 to 3 carbon atoms, carboxamindo, trifluoromethyl, cyano,or nitro; the pyrazolonyl radical, ##STR4## or a substituted pyrazolonylradical such as ##STR5##

The pigments of Formula (I), when compared with the monoazo pigments ofthe Yellow Hansa type, such as for instance the pigment obtained by thecoupling of 5-nitro-2-methoxy-aniline diazo withaceto-acetyl-amino-2-methoxy-benzene, show a much greater tinctorialyield. For instance, in the case of photogravure printing inks, thetinctorial yield is generally more than double.

The pigments of Formula (I) may be prepared by the coupling, accordingto conventional prior art methods, of one mole of the tetrazo-derivativeof a 4,4'-diamino-benzanilide (DABA) of the Formula (III) ##STR6##wherein X₁ and X₂ are as previously defined, with two moles of acoupling agent or of two different coupling agents of the type commonlyutilized in the preparation of benzidine pigments.

Examples of suitable coupling agents include the following:1-aceto-acetyl-amino-benzene; 1-aceto-acetyl-amino-2-methoxy-benzene;1-aceto-acetyl-amino-2-methyl-benzene;1-aceto-acetyl-amino-4-methyl-benzene;1-aceto-acetyl-amino-2,4-dimethyl-benzene;1-aceto-acetylamino-2-chloro-benzene; 1-aceto-acetyl-amino-2,5-dimethoxy benzene;1-aceto-acetyl-amino-2,5-dimethoxy-4-chloro-benzene;1-aceto-acetyl-amino-2,4-dimethoxy-5-chloro-benzene;1-aceto-acetyl-amino-2-methoxy-4-chloro-benzene;1-aceto-acetyl-amino-2-methoxy-5-chloro-benzene; 1-aceto-acetyl-amino-4-nitro-benzene; 1-aceto-acetyl-amino-2,5-dimethoxy-4-cyano-benzene;1-aceto-acetyl-amino-2-ethoxy-benzene;1-aceto-acetyl-amino-4-ethoxy-benzene;1-aceto-acetyl-amino-4-acetyl-amino-benzene;2-aceto-acetyl-amino-naphthalene;1-aceto-acetyl-amino-2-methoxy-5-carboxamido-benzene;3-aceto-acetyl-amino-pyridine; 1-phenyl-3-methyl-5-pyrazolone;5-aceto-acetyl-amino-benzimidazolone;1-aceto-acetyl-amino-2,5-dichloro-benzene;1-aceto-acetyl-amino-2-chloro-5-trifluoromethyl-benzene;1-aceto-acetyl-amino-2-methyl-4-methoxy-benzene; etc.

In order to accelerate the coupling or to influence the size of theparticles or the crystalline shape of the resulting pigment, there maybe added to the coupling mass such additives as water-miscible inertorganic solvents such as methanol, ethanol, ehtyleneglycol, monomethyl-and monoethylenether, aliphatic cyclic ethers such as dioxane, formicacid, acetic acid, dimethylformamide, tertiary azotized bases such astriethanolamine or pyridine, etc. For this purpose there may alsoconveniently be used organic solvents that are insoluble in water, suchas toluene, chlorobenzene, nitrobenzene or tetrahydro-naphthalene.

There may also be admixed non-ionic, anionic or cationic dispersantssuch as: aducts of ethylene oxide with alcohols or fatty acids,condensation products of a naphthalene sulphonic acid and formaldehyde,lauryl-dimethyl-benzyl -ammonium chloride, and, in particular,cetylpyridinium chloride.

The new diazo pigments of this invention precipitate from the reactionmass as the coupling reaction occurs. They are then isolated byfiltering and washed according to known methods. Depending on theparticular end use contemplated, the pigment cake coming from thefilterting stage may be dried and then ground to form a paste, or may beincorporated into organic vehicles by means of a "flushing" operation.The pigments may also be processed with auxiliary substances such as"carrier" resins, in order to obtain granulated material.

The diazo pigments of this invention are suited for the pigmentation oforganic materials, mainly for printing inks for the graphic industry.

These pigments may be utilized also for other purposes such as, forinstance, in oil paints or in water paints, in varnishes, for thecoloring of plastic materials such as polyethylene, polystyrene,cellulose esters, etc.

They may be used in bulk dyeing of cellulose acetate as well as in thepigment printing and dyeing of textiles.

The following examples will further illustrate our invention.

EXAMPLE 1

Into a glass were poured 22.7 parts (=0.1 mole) of4,4'-diamino-benzanilide ##STR7## 150 parts of water, and the mixturewas then heated up to 60° C. There was then added a solution of 91 partsin volume (0.9 mole) of HCl at 30% concentration.

The amine at first passed into solution with a brown coloring and then,upon cooling down, started to precipitate. the whole was permitted tocool down under stirring until a temperature of 20° C. was reached,whereupon the mass was brought down to -4° C. by adding ice to it. Thedisazotation was then carried out by rapidly pouring in 15.2 parts(0.216 mole) of NaNO₂ dissolved in 60 parts of water. The suspensionpassed substantially completely into solution after 5 minutes. Thisachieved, the mixture was stirred for about 60 minutes at a temperatureof less than 0° C. Then a clarification was effected by adding 2 partsof carboparaffin. After 10 minutes the solution was filtered. Therebythere was obtained a clear solution of a yellow-orange hue. Residualexcess of nitrous acid was removed by means of sulfamic acid.

Into a glass having a holding capacity about 6 times greater than thatof the first glass, were poured:

600 parts of water

43.6 parts of aceto-acetyl-meta-xylidine*

22 parts by volume of NaOH 36°Be ##STR8##

The whole was then stirred to obtain a complete solution. To this therewere then admixed:

0.72 part of cetylpyridine chloride and

109 parts of HCOONa.

The solution was then stirred and the pH was gradually brought to aslightly acid value (5-6) by slowly adding at 20° C., a solutioncontaining 27.2 parts of 30% HCl diluted in 80 parts of water. In thesuspension thus obtained there was poured, below the level of theliquid, at 20° C., the previously prepared diazo solution. Couplingoccurred after about 5 hours. The mass was permitted to stand overnight.The reaction mass was then heated in one hour to 90° C. and was thenmaintained at that temperature for about 30 minutes. The resultingpigment was of the following formula ##STR9##

The foregoing pigment was incorporated into a vehicle consisting of 40%of Ca-resinate (Nulix 15®) and of 60% of xylol, thereby obtaining arotogravure printing ink of a yellow hue, characterized by a definitelygreener shade and by a much higher transparency than that of theanalogous benzidine pigment (Pigment Yellow 13, C.I. 21.100).

EXAMPLE 2

Into a glass were poured

250 parts of water

10 parts by volume of NaOH 36° Be

17.8 parts by volume of aceto-acetyl-amino-benzene* ##STR10##

This mixture was then stirred to obtain a solution which was thenbrought down to a temperature of 0-5° C., and then a solution of 10parts by volume of icy acetic acid in 10 parts (by weight) of water wereslowly dripped into it. This mass was then brought up to 20° C. andthere were admixed with it 50 parts of crystalline sodium acetate untilslightly acid pH (5-6) was reached.

Into the thus obtained coupling agent suspension was poured under thelevel of the liquid 0.05 mole of the tetrazo compound prepared asdescribed in the first portion of the preceding example, at atemperature of 20° C. The coupling was achieved in about 5 hours. Thetemperature was then brought up to 80° C. over a period of 40 minutes,and was maintained at 80° C. for 5 minutes. The mass was then cooleddown, filtered, and dried in an oven at 60° C. The resulting pigment wasof the following formula ##STR11##

With a yield very close to the theoretical, there was obtained ayellowish powder that, when incorporated into a vehicle consisting of40% of calcium resinate and of 60% of xylol, yielded a rotogravureprinting ink of a yellow tone appreciably more greenish and moretransparent than the analogous benzidine pigment (Pigment Yellow 12,C.I. 21.090).

EXAMPLE 3

The same procedure as described in Example 2 was followed, except that0.1 mole of 2-methoxy-1-aceto-acetyl-amino-benzene, of the formula##STR12## was employed as the coupling agent. Thereby there was obtaineda pigment of a yellow hue. This pigment was of the formula ##STR13##

Incorporation of this pigment into an organic vehicle consisting of 40%of calcium resinate (Nulix 15®) and of 60% of xylol, yielded an inkhaving a yellow tone with a markedly more greenish nuance and aconsiderably higher transparency than is shown in the analogousbenzidine pigment (Pigment Yellow 14, C.I. 21.095).

EXAMPLE 4

This example was similar to Example 2, however using 0.1 mole of4-ethoxy-1-aceto-acetyl-amino-benzene, of the formula ##STR14## wasthereby obtained a pigment of yellow hue, this pigment being of theformula ##STR15##

When this pigment was incorporated into a vehicle consisting of 40% ofNulix 15® and of 60% of xylol, there resulted a rotogravure printing inkendowed with the same characteristics as those of the precedingexamples.

EXAMPLE 5

This example was similar to Example 2, but using 0.1 mole of1-aceto-acetyl-amino-2,5-dimethoxy-4-chlorobenzene as the couplingagent, to thereby obtain a yellow pigment of the formula ##STR16##

When this pigment was incorporated into a vehicle consisting of 40%Nulix 15® and 60% of xylol, it yielded a rotogravure printing ink havinga yellow tone with a much more greenish tint and with a considerablyhigher transparency than that obtainable with the "Giallo Segnale LuceR" (Pigment Yellow 83).

EXAMPLE 6

This example was similar to Example 2, however using as the couplingagent 0.1 mole of 1-phenyl-3-methyl-5-pyrazolone. There was therebyobtained a pigment of the formula ##STR17##

When this pigment was incorporated into a vehicle consisting of 40% ofNulix 15® and of 60% of xylol, it yielded a rotogravure printing ink ofan orange shade and having a more greenish tint and a considerablyhigher transparency than that obtainable fromthe analogous benzidinepigment (Pigment Orange 13, C.I. 21.100).

EXAMPLE 7 Preparation of the various substituted4,4'-diamino-benzanilides used in Examples 8-11. (a)4,4'-diamino-2'-methoxy-benzanilide, ##STR18##

200 parts of thionyl chloride were admixed over a 30 minute period witha suspension of 200 parts of paranitrobenzoic acid in 600 parts ofdichlorobenzene and 1.9 parts of dimethylformamide at 80° C. The mixturewas gradually heated to 115° C. and kept at this temperature for 4 hoursuntil a complete solution had been obtained. Excess thionyl chloride waseliminted by distillation under vacuum at 115° C. Then, over a 30 minuteperiod, 202 parts of 2-methoxy-4-nitro-aniline were added. The whole washeated to 140° C. for 3 hours, then was cooled to room temperature andthe resulting precipitate was filtered by washing, first with methanoland thereafter with water. The dinitro derivative aqueous paste wassuspended in 1,700 parts of water and heated to 90° C. At thistemperature an aqueous solution of 593 parts of Na₂ S₂ was admixed overa period of 1 hour, and the whole was maintained at 90-95° C. for afurther 3 hours. After cooling to 20° C., the product was filtered,washed with cold water and dried at 60° C., thus obtaining high yieldsof 4,4'-diamino-2'-methoxy-benzanilide (melting point: 160°-161° C.).

(b) 4,4'-diamino-2'-chloro-benzanilide, ##STR19##

By operating as described under (a) above, but using, instead of 202parts of 2-methoxy-4-nitro-aniline, 207 parts of 2-chloro-nitro-aniline,high yields of 4,4'-diamino-2'-chloro-benzanilide were obtained (meltingpoint: 194°-197° C.).

(c) 4,4'-diamino-2'methyl-benzanilide, ##STR20##

By operating as described under (a) above, but using, instead of 202parts of 2-methoxy-4-nitro-aniline, 183 parts of2-methyl-4-nitro-aniline, high yields of4,4'-diamino-2'-methyl-benzanilide were obtained (melting point:111°-115° C.).

(d) 4,4'-diamino-2',6'-dichloro-benzanilide, ##STR21##

By operating as described under (a) above, but using instead of 202parts of 2-methoxy-4-nitro-aniline, 248 parts of2,6-dichloro-4-nitro-aniline, high yields of4,4'-diamino-2'6'-dichloro-benzanilide were obtained.

EXAMPLE 8

3.86 parts (0.015 mole) of 4,4'-diamino-2'-methoxy-benzanilide (preparedin Example 6A) and 25 parts of water were poured into a beaker. Thetemperature was raised to 60° C. and then 13.6 parts by volume of 30%HCl were added. The whole was allowed to cool, under stirring, to 20° C.and the temperature of the mass was then lowered, by the addition ofice, to a temperature of -4° C. Diazotation was carried out by rapidlypouring into the beaker 2.28 parts of NaNO₂ (0.033 mole) dissolved in 10parts of water.

After 5 minutes essentially the entire suspension had gone into asolution. The solution was stirred for about 60 minutes at a temperatureof less than 0° C. It was clarified by adding 0.5 parts of activatedcarbon and, after 10 minutes, by filtering. A limpid yellow-brownsolution was obtained, from which the excess nitrous acid was removed bymeans of a sulfamic acid aqueous solution.

90 parts of water, 3.3 parts by volume of 36° C. Be NaOH, 6.22 parts of2-methoxy-1-aceto-acetyl-amino-benzene (0.03 mole) were poured into abeaker having a capacity five times greater than that of the previousbeaker. The whole was stirred until a complete solution was obtained.0.108 part of cetyl pyridinium chloride and 16.4 parts of sodium formatewere then added.

The whole was stirred and the pH value was brought to a slightly acidvalue (5-6) by slow drip-wise addition of a solution containing 4.1parts by volume of 30% HCl diluted with 15 parts of water.

The tetrazo solution previously prepared was poured into the suspensionthus obtained, under the liquid level, at 20° C. Coupling was completeafter about 3.5 hours. The reaction mass was heated up to 90° C. and waskept at this temperature for about 30 minutes. The resulting precipitatewas cooled, filtered, thoroughly washed and dried in an oven at 60° C. Ayellow pigment powder was thus obtained. The pigment was of the formula##STR22##

When this pigment was incorporated with a carrier consisting of 40% ofcalcium resinate and of 60% of xylene, there resulted a highlytransparent, yellow-green rotogravure ink having a staining power higherthan that of the corresponding benzidine pigment (Pigment Yellow 17,C.I. 21.105).

EXAMPLE 9

The procedure of Example 8 was followed, however employing 3.93 parts of4,4'-diamino-2'-chloro-benzanilide (prepared in Example 6b) as thediazotizable base. A yellow-green pigment was thus obtained. Thispigment was of the formula ##STR23##

When this pigment was incorporated with an organic carrier containing40% of calcium resinate and 60% of xylene, there resulted a rotogravureink exhibiting a less intense and green shade than that obtained inExample 8.

EXAMPLE 10

The procedure of Example 8 was followed, however employing 3.62 parts of4,4'-diamino-2'-methyl-benzanilide (prepared in Example 6c) as thediazotizable base. A yellow-green pigment was thus obtained. Thispigment was of the formula ##STR24##

When incorporated with an organic carrier made up of 40% of calciumresinate and of 60% of xylene, there resulted a rotogravure ink having aslightly greener shade than that obtained in Example 8.

EXAMPLE 11

4.44 parts (0.15 mole) of 4,4'-diamino-2', 6'-dichloro-benzanilide(prepared in Example 6d) and 25 parts of water were poured into a beakerin order to prepare the tetrazo according to the procedure set out inExample 8.

180 parts of water, 6.1 parts of 36° Be NaOH, 8.13 parts ofaceto-acetyl-2,5-dimethoxy-4-chloroanilidine were poured into a beakerhaving a capacity 5 times larger than the preceding beaker, and thewhole was stirred until a complete solution was obtained.

It was cooled with ice to 0° C. and subsequently, under intensestirring, the pH was brought to a slightly acid value by permitting asolution of 5.6 parts of Al₂ (SO₄)₃.18 H₂ O dissolved in 30 parts ofwater to slowly drip into the solution. The suspension thus obtained washeated to 20° C. The previously prepared tetrazo solution was thenpoured in, under the liquid level. Coupling was complete after 4 hours.The reaction mass was heated up to 90° C. and maintained at suchtemperature for 30 minutes. The resulting precipitate was filtered,thoroughly washed, and then dried at 60° C. A yellow pigment powder wasobtained. The pigment was of the formula ##STR25##

When the pigment was incorporated with a carrier containing 40% ofcalcium resinate and 60% of xylene, there resulted a rotogravure inkexhibiting considerable transparency and sunlight stability.

Variations can, of course, be made without departing from the spirit andscope of the invention.

Having thus described the invention, what is desired to be secured byLetters Patent and hereby claimed is:
 1. A diazo pigment of the formula:##STR26##
 2. A diazo pigment of the formula: ##STR27##